Tropospheric Influence in GNSS Positioning

Atmospheric influences, mainly caused by ionospheric and tropospheric conditions, lead to delays and distortions of GNSS signals that travel from satellites to receivers on Earth. This impact must be considered for projects that require high positioning and navigation accuracy. The troposphere dominates in areas with a large amount of water vapour and can also cause measurement errors due to changes in signal propagation speed. In this work, the tropospheric influence on GNSS positioning was analysed. The focus is on their cause, how they affect the accuracy of GNSS measurements, and the methods and technologies used to reduce or eliminate this influence. A 3D geodetic network of permanent stations was levelled using different empirical tropospheric models. Understanding and correcting these factors are important for improving GNSS technology's accuracy, reliability and practical use in modern geodetic and scientific research. The tropospheric delay is usually modelled in the zenith direction and is called the zenith tropospheric delay. As the zenith angle increases, the delay itself increases. So-called reduction functions obtain the relationship between the zenith and oblique delays. The GNSS-Lab Tool software and data collection and processing methods were used to calculate and obtain the zenith tropospheric delay (ZTK) value.